Checker

Validate user sign-ups in real time via API and protect your business instantly

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Users on digital platforms frequently sign up with temporary or fake email addresses, distorting your analytics, draining server resources, and spiking support requests.

Checker solves this with its Pro Scrape Technology, combining OmniCrawler (for detecting temp domains), and DomainCatch (for spotting suspicious signups).

With a real-time response time under 200ms and a growing list of over 170,000+ temporary email domains, Checker blocks fake signups before they ever hit your system—so you can focus on real users.

TL;DR

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Optimize resource usage and protect revenue with accurate, clean user data
Block fake signups instantly with real-time email and domain verification

At-a-glance

Overview

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Checker blocks temporary or fake signups before they enter your system.

Why Traditional Email Verification & OTP Are Not Enough

Checker instantly flags suspicious email addresses before they can create an account, using a 170,000+ domain blacklist and sub-200ms API response.

  • Temporary emails are on the rise – Services like Temp Mail let users flood platforms with disposable addresses.
  • Standard email checks are weak – They verify if an email exists but can't detect temporary or suspicious domains.
  • OTP can be easily bypassed – Disposable inboxes can instantly receive OTPs, defeating their purpose.
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Prevent resource waste and protect your revenue model from fraud.

Cut costs, boost performance

By stopping junk signups, Checker helps you use server resources wisely and maintain reliable, profitable marketing funnels.

  • Reduce wasted server load from fake accounts and spam signups
  • Ensure fair access by blocking trial hoarders and multi-account users
  • Protect business decisions with clean, trustworthy user data
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Securely manage API access and monitor threats to protect your email infrastructure.

Integrate and automate in minutes

Checker is built for fast setup and low effort ongoing defense—with integrations for any team.

  • Connect via API for real-time checks across any workflow
  • Use the WordPress plugin for fast protection without custom coding
  • Track everything live with a real-time analytics dashboard

Checker helps you stay one step ahead of fake users. With powerful real-time email detection, easy setup, and airtight data protection, you can stop sign-up fraud before it costs you.

Block bad actors and grow with confidence—get lifetime access to Checker today.

From the founders

Company and product FAQs

What are your past projects, failures, or successes in your career?

I have over five years of experience in the marketing industry. Throughout my career, I’ve worked on various e-commerce and SaaS projects. My biggest achievement was exiting a Shopify app I founded two years ago. On the other hand, my most valuable lesson came from a failed email marketing tool—I painfully learned the consequences of launching without proper user validation.

Which third-party tools are critically essential to your product?

Our product does not depend on any 3rd party application.

Where is your customer data stored?

All customer data is securely stored on servers located within European regions. Our GDPR-compliant infrastructure is designed to ensure maximum data security.

How many customers do you have today?

We launched Checker in beta approximately four months ago and currently have over 100 active users. Most of them are SaaS companies, e-commerce sites, and content platforms.

What is the origin of the idea behind Checker?

The idea for Checker came from problems I encountered while managing my own SaaS platform. We were being exploited by fake users and temporary email addresses. After researching available solutions, I found most were either too expensive or lacked comprehensive features. We began building our own tool and soon realized this was a common problem faced by many businesses—not just ours. That’s how Checker was born—a solution born out of necessity.

Why are we passionate about Checker?

We believe the digital world should be a safe and honest place. Fake users and malicious sign-ups threaten the integrity of the digital ecosystem. With Checker, we help businesses focus on real users, improve data quality, and allocate their resources more efficiently. Every fake registration we block brings us one step closer to a more trustworthy internet. This mission drives us daily and fuels our desire to keep improving.

What is the #1 thing you want to gain from your AppSumo campaign?

Our top goal with the AppSumo campaign is to gather feedback from businesses of different sizes and sectors. Testing our product with a wider user base will help us better understand various use cases and tailor Checker to meet the diverse needs of our customers. The AppSumo community is known for its tech-savvy, feedback-rich users, and their insights will be crucial in taking our product to the next level.

What are your plans for the customers, cash, and learnings from AppSumo?

We’ll invest AppSumo resources in three areas: improving the product (including RiskyIPs and platform plugins), expanding customer support, and strengthening our infrastructure for speed and scalability. We view AppSumo users as key partners whose feedback will shape Checker’s future.

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